Quorum sensing Flashcards
What is quorum sensing?
- intercellular signalling (cell to cell communication)
- sensing “like” cells
- survey environment for like cells and share small specific molecules
What is triggered when a sufficient concentration of signalling molecule is present?
- specific gene expression triggered
What is the advantage of quorum sensing?
- ganging up
Where is QS carried out?
- any prokaryote with regulatory pathway
- gram neg
what does QS involve?
- diffusible molecules of acylated homoserine lactone (AHL)
what happens when AHL is at sufficient concentrations?
- induces activator proteins that trigger specific gene transcription
What causes light emission in bioluminescent organisms deep in the ocean?
- vibrio fischeri
- enzyme luciferase
What regulates lux operons when AHL levels are sufficient?
- LuxR
What do QS systems control?
- genes involved in pathogenesis of certain bacteria
What is a synergistic relationship?
- bacteria gets nutrients, fish can see
What kind of bacteria is P. aeruginosa? What does it cause?
- opportunistic
- infections in lungs, skin and urinary tract
What activates virulence genes of p. aeruginosa? what activates the second subset of virulence genes?
- LasI and LasR
- Rhl system
What is Las system required for?
- virulence of p aeruginosa and mature biofilm development
What does vibro cholerae do?
- regulates biofilm formation and expression of virulence genes
What does QS of cholerae do to biofilm formation and virulence gene expression?
- inhibits functions